Did you know that 10 companies account for 96% of the $1.15 trillion in ETF assets? BlackRock (NYSE:BLK), State Street (NYSE:STT) and Vanguard alone account for 83% of the market share, and 41 ETF producers control just $196 billion in assets.

Of course, while those companies have the most firepower, it doesn’t mean they were solely responsible for all the fireworks in the past year. Companies big and small had a part in some of the most noteworthy ETF launches so far in 2012.

As we look back on some of the new ETFs introduced in the first half of the year and provide some thoughts about the second half of the year, we can be certain of one thing — change is afoot. Be sure to stay tuned as the ETF industry continues to heat up.

Leading off with the earliest fund introduction of 2012, I’ll start with the SPDR S&P Small Cap Emerging Asia Pacific ETF (NYSE:GMFS), which started trading Jan. 11 — giving investors the first ever opportunity to invest in small caps throughout the region.

Prior to the fund’s introduction, there were country-specific funds like the IQ Australia Small Cap ETF (NYSE:KROO), but nothing farther-reaching. Three weeks later, BlackRock introduced the iShares MSCI All Country Asia ex Japan Small Cap Index Fund (NASDAQ:AXJS). The two big differences between the funds: the iShares fund has 17.6% of its assets invested in South Korea while the SPDR has none; secondly, the SPDR has 42% of its fund invested in Taiwan, double the iShares weighting.

In the future, look for additional small-cap fund introductions.

Next up is the event of the year: Bill Gross introduced the PIMCO Total Return ETF (NYSE:BOND) on Feb. 29 — the long-awaited ETF version of his highly successful open-end bond fund. In less than four months, the ETF accumulated $1.7 billion in assets.

That’s not a big number when you consider that Vanguard and iShares both have total bond market funds with assets greater than $15 billion. However, when you calculate the assets gathered on a yearly basis, PIMCO is much farther along in its development. Especially if you consider that Gross’ fund is actively managed while the other two are passive index funds. With just 30 or so actively managed funds available, investors clearly are not taking to any of these funds — with PIMCO the rare exception.

I don’t see any reason why Gross can’t duplicate the success he’s had with his mutual fund. This could be a game-changer for active ETFs.

State Street introduced three actively managed ETFs on April 26. The one that stands out for me is the SPDR SSgA Global Allocation ETF (NYSE:GAL), which is a fund-of-funds that invests in equities, fixed income and real estate around the globe and uses 17 State Street ETFs and the PowerShares DB Gold Fund (NYSE:DGL) to make the portfolio sing.

At 0.35%, investors get a portfolio with 35% U.S. equities, 24% international equities, 29% U.S. fixed income, 4% international fixed income, 7% U.S. and international REITs and 1% commodities.

Being a new fund and actively managed to boot, it’s near impossible to guess how it’s going to perform long-term. U.S. News, however, gives it a “best fund” rating for Global Equities seeking capital appreciation. Frankly, if simple and cheap is your objective, I don’t think you can do any better than this relatively unknown gem.